Release 0.9.0

Fix build with clang 3.5 (Apple LLVM 6.0)

Release preparation (#187)

Merge pull request #174 from tribal-tec/master

Cleanup

Merge pull request #136 from chevtche/master

Fixed some consts

Merge pull request #107 from tribal-tec/rel_prep

Release preparations

Merge pull request #76 from tribal-tec/master

Release 0.3 preparations

Update version and documentation